The present invention relates generally to the field of firearms, and more particularly, but not exclusively, to an improved cartridge design and firing pin for the same.
The most popular cartridge used when firing a firearm is the 0.22 caliber rimfire cartridge. Rimfire ammunition is often used because it is relatively inexpensive as compared to center fire ammunition. Thus, rimfire ammunition allows greater use of the firearm with less cost for such activities as recreational shooting, weapons training, hunting, and the like. Rimfire ammunition may also be used with firearms that conventionally fire more expensive ammunition, such as military weapons. These types of weapons may be adapted to fire the lower cost rimfire ammunition during training exercises with the firearm, thus saving on training expense.
One example of a rimfire cartridge is illustrated in FIG. 1 and designated generally at 10. Rimfire cartridge 10 includes a bullet 12 connected to a casing 14 at crimped portion 17. Opposite bullet 12, the casing 14 has a rearward end member 16. Casing 14 also includes a wall 22 having an inner surface 22a and an outer surface 22b. Wall 22 and end member 16 define a hollow interior 24. Projecting radially outward from wall 22 and extending between wall 22 and end member 16 is annular outer rim 18. Outer rim 18 defines an annular pocket 20 communicating with hollow interior 24. As is well known in the art, when the cartridge 10 is manufactured, a quantity of fluid priming composition 28 is spun into annular pocket 20 and allowed to dry. A quantity of powder 26 is then placed within hollow interior 24 of casing 14. In order to fire the cartridge, a firing pin configured to sharply strike casing 14 at outer rim 18 crushes the priming composition in annular pocket 20 which in turn ignites powder 26. Powder 26 burns rapidly and creates gas as it burns. The pressure from the gas forces bullet 12 from crimped portions 17 and propels bullet 12 down the barrel of the firearm.
One of the drawbacks with such rimfire cartridges is that casing 14 suffers from low strength and is prone to failure, particularly at rim 18, when casing 14 is used for a high velocity cartridge. Thus, even though the capacity of casing 14 can hold a sufficient quantity of powder to produce a high velocity cartridge, casing 14 will fail due to the higher pressures generated by the larger quantity of burning powder. This results in less powder being used with the cartridge to minimize the risk of casing failure. The reduced amount of powder causes less gas pressure to be generated by the burning powder. This in turn lowers the velocity and the energy of the bullet when it is fired.
There remains a need for a cartridge which effectively addresses the problems of casing strength while maintaining the advantages associated with rimfire cartridges. The cartridge should be capable of use in existing firearms with minimum modification to its components. The present invention is directed towards meeting these needs, among others.
One form of the present invention is directed to a cartridge that includes a casing having a wall and a projection extending inwardly from the wall adjacent the end member of the cartridge. The projection and the end member of the casing form a recess for priming composition to be placed therein.
According to one aspect of the invention, a cartridge for a firearm is provided. The cartridge includes a bullet coupled to a casing. The casing includes a cylindrical wall that extends from a first end to an end member opposite the bullet. A hollow interior is formed by the wall and the end member. A flange extends radially outwardly from the cylindrical wall at the end member. A projection connected with the wall extends radially inwardly into the hollow interior. A recess for receiving priming composition is formed by the projection and the end member.
According to another aspect of the invention, a method for making a cartridge for a firearm is provided. The method includes (a) providing a casing with a cylindrical wall and a length extending between a first end and an end member, a hollow interior defined by the wall and end member, and a flange adjacent the end member that extends radially outwardly from the cylindrical wall; (b) forming a projection that extends from the wall into the hollow interior such that the projection and the end member form a recess; and (c) placing priming composition in the recess. In one embodiment, the method further includes (d) placing powder in said hollow interior; and (e) placing a bullet in the first end of the casing.
According to yet another aspect of the invention, a method for making a cartridge for a firearm is provided. The method includes: (a) providing a casing having a centerline axis and a cylindrical wall about the axis that has a length extending between a first end and an a end member, the wall and end member defining a hollow interior, and the cylindrical wall having an inner surface that is spaced a first distance from the centerline axis; (b) forming a recess in the interior of the casing by placing a projection on the cylindrical wall so that the recess is spaced a second distance from the centerline axis that is less than the first distance; and (c) placing priming composition in the recess.
According to a further aspect of the invention, a firing pin for a firearm is provided. The firing pin includes a body having a centerline axis extending between a rearward end and a striking end of the body. The striking end has a leading point spaced a first distance from the centerline axis so that it strikes a cartridge having a priming composition recess spaced a corresponding distance from the centerline of the cartridge casing. The striking end also includes a trailing point spaced the second distance from the axis to strike an outer rim of a rimfire cartridge.
These and other forms, embodiments, aspects, features and objects of the invention will be apparent from the following description of the preferred embodiments.